Process and apparatus for making laminated vulcanized fiber



Jan. 15, 1935. w. M. SHOEMAKER, JR 1,988,340

PROCESS AND APPARATUS 30R MAKING LAMINATED VULCANIZED FIBER Original Filed April 25, 1929 2 Sheets-Sheet 1 Jan. 15, 1935. w. M. SHOEMAKER, JR 1,988,340

PROCESS AND APPARATUS FOR MAKING LAMINATED VULCANIZED FIBER Original Filed- April 25, 1929 2 Sheets-Sheet 2 gmemtoc 3 Patented Jan. 15, 1935 PATENT oFr cE PROCESS AND APPARATUS FOR MAKING LAIMINATED VULCANIZED FIBER William M. Shoemaker, Jr., Kennett Square, Pa.I

assignor to National vulcanized Fibre Company, Wilmington, Del., a corporation of Delaware Continuation of application Serial No. 357,971, April 25, 1929. This application February 15, 1930, Serial No. 428,580

15 Claims.

The present application is a continuation of application Serial No. 357,971 filed April 25, 1929.

My invention relates to' the manufacture of indurated fiber. As exemplified by Patent No. 897,758 to Marshall and Patent No. 1,675,666 to Shoemaker, this type of material has heretofore been made by passing several webs or sheets of cellulosic material, preferably but not necessarily an all cotton cellulose paper, through a gelatinizing'or parchmentizing bath of suitable concentrationv and temperature and then combining or laminating said gelatinized or parchmentized webs or sheets into one I'nulti-ply web or sheet by the means of suitably applied heat and pressure. Among the parchmentizing or gelatinizing agents that have been mentioned in the prior art are included aqueous solutions of metallic salts such as zinc chloride and dilute acids such as sulphuric. These agents serve to chemically hydrate, partially hydrolize or gelatinize the cellulose fiber of the individual sheets,'thus enabling them to coalesce and become indissolubly united or welded into a more or less homogeneous multiply sheet under the subsequent application of .heat and pressure. By leaching and puring out the treating agent and subsequently drying the sheet, a hardened material results having greatly improved characteristics as compared with the cellulose webs originally subjected to the chemical and physical treatment. The term vulcanized fiber is usually applied in the art to indurated material which has been made by the use of a solution of a metallic salt such as zinc chloride' while the term leatheroid is usually reserved for material which has been made with a dilute acid.

such as sulphuric.

In the following description and claims the term paper is to be used in its ordinary significance in the art; namely, a sheet of cellulosic' agent or gelatinizing bath, etc.) to impart thereto a hardness and density not ordinarily possessed by untreated paper.

An important object of my present invention is-to provide a new and improved method and apparatus whereby a continuous sheet or web of indurated fiber maybe produced of greater thickness than has previously been accomplished or considered practical. I

The essence of the portion of the combination hereinafter to be described which renders the temperatures.

possible tocontrol or vary the treating and lami foregoing object possible of accomplishment is the provision of means for the separate impregnation and heat and pressure treatment of each individual web which" enters into the make-up of the final product. According to one of the prior art methods, it was the usual practice to subject a plurality of separated webs to the action of one and the same gelatinizing bath and then to superpose the webs and conductthem over, around and between cylinders which provide the requisite heat and pressure to combine the separate webs into one integral, multi-ply product. This prior art process is necessarily limited in the number of webs which it can chemically treat and laminate due to the fact that the heat can reach all the webs only by conduction through the entire thickness of the product. Furthermore, the process is very slow, particularly due to the fact that the pressure which consolidates the sheets must at the same time force the excess gelatinizing agent from between all the webs has to be expelled from only one web at a time.

Another object is to provide a new and improved method and apparatus for producing a laminated or multi-ply web of indurated fiber having a greater homogeneity and density than had previously been possible.

The essence of the portion of the combination hereinafter to be described which renders the foregoing object possible of accomplishment isthe provision of means whereby the conditions under which each individual sheet is chemically treated and subjected to heat and pressure may be selectively controlled or varied. As is known in the art, paper of different basic stock, density, absorption, etc. may require treating solutions having different concentrations, temperatures, purity, etc. to produce products having desired properties. For instance, a dense, highly calendered paper requires treatment with a more fluid agent indicated by a lower Baum. Also, a highly calendered or -low absorption hard" paper is more diflicult to treat with agents above certain By means of my invention it is nating conditions for any one or more of the in-'.

it possible for the first time to produce a multiply web of indurated fiber under optimum conditions of concentration, temperature" and state of purity of reagent as well as temperature and pressure of lamination.

Another object is to provide a new and improved method and apparatus by means of which may be produced a multi-ply web of indurated fiber from a very soft, open, absorbent paper.

The essence of the portion of the combination hereinafter to be described which renders the foregoing object possible of accomplishment is the compactness with which I have arranged the various elements of the apparatus in reference to the individual webs which enter into the fabricationof the m'ulti-ply web of' indurated fiber. Prior processes and apparatuses have invariably required the unbatching or unwinding of the rolls of paper from considerable distances and then the dipping or immersion of the individual plies through the treating agent and the lifting or drawing of the individual webs, heavily weighted with the excess treating agent up from the bath overand around the drums or cylinders by means of which the heat and pressure necessary for the laminating step are to be applied. It has, therefore, been impractical to utilize a very open paper or felt such as would naturally lack the tensile strength necessary to permit it to be drawn through the bath and then to be raised and conducted to the drums or cylinders. In my apparatus the paper is unwound in close relation to the treating bath and has a relatively short, almost horizontal, travel to the heat and pressure applying cylinders. Thus it is rendered practical to use a. paper or. felt of greater softness, open.-

- ness and absorption and lower tensile strength than had previously been considered possible.

Still another object is to provide a new and improved method and apparatus having great flexibility of operation, whereby one or more webs of any desired number of plies may be produced.

v The essence of the part of the combination hereinafter to be described which renders the foregoing object possible is the provision of means for leading the laminated web or webs of indurated fiber ofl at any one or more selected positions along the apparatus.

A further object is to provide a new and improved method and apparatus by means of which a laminated web of indurated fiber of great thickne'ss may be continuously produced at a greatly I increased rate (speed in lineal feet per minute).

The essence of the part of the combination hereinafter to be described which renders the foregoing object possible of accomplishment is the portion. of the process and apparatus whereby each individual web but the first is separately superposed upon and combined by the means of heat and pressure-with a web of progressively increasing thickness which has already been subjected to the consolidating action of heat and pressure. As has already been pointed out. when a plurality of chemically treated webs are superposed and combined over, around and between drums or cylinders as in the prior art, the process is necessarily slow (five to fifteen lineal feet per minute) due to the fact that the heat must be conducted through all the webs and to the further fact that the excess treating agent must be forced from between all the webs at the same time. In the process and apparatus of the present invention, the heat and pressure are first applied to the first webto form a base web and then to each individual web'separately and B-1 cessively as it is laid upon and is consolidated with the previously consolidated web or webs. Hence, the heat has to be conducted through only one web at a time and the excess treating agent expelled from only one web at a time. Thus, it has been found possible to speed up the process to as high as fifty lineal feet per minute.

A further object is to provide a new and improved method and apparatus by the means of which a laminated productof indurated fiber may be produced in which all the plies are of exactly the same length.

The essence of the part of the combination hereinafter to be described which renders the foregoing object possible of accomplishment is the superposing and consolidation of the constituent webs in a level or fiat plane as opposed to the curved surfaces of the prior art. In the prior art there are two general methods of producing a laminated web of indurated fiber. The first method consisted in winding a single layer of gelatinized paper around a drum and upon itself until the desired thickness was obtained. The sheets are then produced. by stripping and cut ting the laminated material from the drum. Naturally, the ply which had been wound on the drum first is of shorter length than the others and when the stripped material is flattened out, strains are set up in the material which produce an undesirable warping in the dried material. Thesecond general method of the prior art consisted in continuously laminating a plurality of treated webs of indefinite length by conducting the superposed webs over, around and between heated drums or cylinders. Since the superposed webs dry and set while in a curved condition, a warping tendency is produced in the final product. In my invention, each of the constituent webs are of exactly the same length due to the fact that-the consolidation of the webs is carried out while they are maintained in fiat condition. Thus, the warping tendency so characteristic of the prior art product is entirely eliminated.

A further object is to provide a new and improved method and apparatus by the means of which a laminated web of indurated fiber may be produced having either no selvage or a. minimum of selvage, thus reducing waste to a minimum. I

The. essence of the part of the combination hereinafter to be described which renders the I foregoing object possible of accomplishment resides in the arrangement of the supply rolls of paper in relation to each other and to the finished web of indurated fiber as it is being formed so that the individual webs may be withdrawn from their supply rolls and superimposed with their edges in exact alinement or fiush relation to each other and to the laminated web. The supply rolls are independently mounted on the machine so that they may be readily adjusted axially or laterally in respect to theapparatus.

A still further object of the invention is to provide an apparatus for the formation of multiply webs of indurated fibenin which the source of supply for any one or more of the constituent webs of the laminated product in process may be replenished without interrupting the process.

The essence of the part of the combination to be hereinafter described to which can be attributed the foregoing object is the provision of at least two sources of supply for each one of the.

constituent webs of the laminated product, in opeach couple being whenever one source is exhausted the second can be drawn upon without interrupting the continuity of the process.

other objects and advantages of the invention will be set forth as the detailed description thereof proceedsor else will become apparent from such description. In order that the invention, may be understood readily and the advantages thereof more fully and easily appreciated, reference should be had to the accompanying drawings, wherein I have illustrated a mechanical embodiment of an apparatus in the form at present preterred by me.

In the drawings;

Fig. 1 is a view in longitudinal section of a portion or an apparatus embodying the invention; I Fig. 2 is a similar view showing an additional br extended portion of the apparatus;

Fig. dis a view in side elevation of a fragmentary portion of the apparatus;

Fig 4 is a transverse sectional view taken on the line 4-4 of Fig. 3; and

Fig. is a sectional view in reduced size or a fragmentary portion of the apparatus indicating a feature of operation which is practicable in an apparatus embodying the invention.

In-the' drawingsI have shown a portion of the structure in Fig. l, the broken line at A indicating that the structure as shown in that figure may be extended indefinitely, within practical limits, and the dash and-dot line B indicating the plane within which the righthand end of Fig. 1 terminatesand that within which the lefthand endof 2 begins. The showing is made in this way because it is not practical to show satisfaetorily'ln a single figure the apparatus in its rulilensth- The portion of the structure illustrated in Figs.

1, 3 and 4 comprises a frame having a base or supporting portion, indicated as a whole at 1, from which rise upright posts or standards 2, which posts are arranged in couples, one post of located at one side vof the base and the other post of said couple being located at the Oppos te side of said base. These posts are each provided with brackets 3 .which are secured to the side thereof as indicatedinj Fig. 1. These brackets are provided with notches, asindicated at 4, which notches constitute bearings in which the opposite ends of the mandrels 5 are supported. These mandrels support rolls of paper 6 and '7. As will be apparent, these mandrels and the rolls carried thereby are supported independently of each other, and any roll and its 'mandrel of the top series may .be removed without disturbing any other roll of the series or any one of the rolls 6 of the lower series. However, when all of the rolls are full, as indicated in Fig. 1, it is obvious that none of the rolls,6 of the lower series (except that at the righthand end of the series) may be removed without first removing one or more rolls '1 of the top series.

In the construction as shown, the paper webs "are illustrated as being drawn from the bottom series ofrolls 6. There are shown in each series seven rolls of paper. The webs of paper, which for convenience of description I shall designate by the reference numeral 11, which are drawn from the first four rolls 6 (counting from the left of Fig. 1) of the bottom series are united to form a single four-ply web or sheet 12, while the webs 13 drawn from the last three rolls 6 of the bottom series are united to form a single three-ply web 14. As has been indicated already, the base 1 may be made of such length as may be desired, and

there also may be such number of pairs of posts 2 as may be necessary to supply the number of plies of paper whichit is desired to employ in the making of a vulcanized fiber sheet or web; or the number of pairs of posts employed may be such as to provide the rolls necessary to supply the number of sheets required in the productionof a plurality of vulcanized webs of fiber, in the manner as illustrated in the drawings.

While the rolls 6 and '7 are located in series one above the other, as illustrated in Fig. 1, and each roll is supported independently of the other, it will be apparent that when the paper from a roll 6 or the rolls 6 is exhausted the operation may be continued without interruption by thereafter taking the paper from the roll '7 or the rolls '7 of the top series. Assuming that the paper has been unwound from a roll, and that the rear end portion thereof, as indicated at 15, has passed from the mandrel 5 of such ,roll, as indicated in Fig. 5 of the drawings, it will be seen that the paper may then be taken from a roll 7 in the top series located directly above that from which all that the ply of paper from the top roll should be carried down on the lefthand side of the mandrel 5, so that the latter may be more readily removed from its bearings. After the removal of the latter from its bearings the mandrel of the top roll is removed from its bearings and lowered into the lower bearings, whereupon a new roll may be placed in the top bearings, thus providing .practically at all times a supply of rolls in the top series from which the paper may be taken after it has been removed from the rolls of the lower series. By this means an uninterrupted continuation of the operation may be practiced.

The webs of paper taken or withdrawn from' the rolls are conveyed through solutions of zinc relation to the respective rolls of paper of either the top or bottom series. The solution of zinc chloride in these containers should be of suitable strength, say about 70 Baum, and of atemperature which may range from room temperature to about 35 C. The solution held in the containers 21 ,preferably consists of a water solution of zinc chloride, as hereinbefore indicated. In order to guide the ,webs of paper through the solution held in the said containers 21 I have provided guides 25 supported at their opposite ends-upon the opposite sides of the said containers, which guides may be stationary or rotatable. The bot tom portion of each of these guides is located a distance above the bottom of the container in which it is located so as to permit the webs of paper 11 or 13 to travel underneath the same and thereby be caused to pass through the solution held in the said container. Each of the containers is associated and cooperates with a couple of pressure and heat-applying rollers, which may be described as being located in front thereof. These heat-applying rollers may be of the same diameter, as shown, or, if desired, the diameter of the top roller may be increased so that it will be greater than that of the lower roller. In such event it should be rotated so that the speed of movement of its surface would be the same as that of the surface of the lower roller of smaller diameter. 'By so increasing the diameter of the top roller of a pair of rollers the period of time during which heat is applied to a web or ply of paper may be increased.

The front of the machine will be regarded as that end which is located at the lefthand side-of Fig. 1 of the drawings.

By the construction as illustrated, in which a stationary guide or single guide is provided for each of the containers 21, it is possible to make the said guides of greater diameter than has been practical in the apparatus of this character heretofore employed in the manufacture of vulcanized fiber board.

The heat and pressure-applying rollers are arranged in couples, which couples are designated respectively by the letters a, b, c, d, e, j, and a. The-couple of rollers a is the first of the series of couples of rollers and it is located to the left It will be noted of the first of the containers 21. that the webs of paper 11 and 13 afterthey have passed underneath and beyond the guides 25 are inclined upwardly and extend in parallel relation to the inclined bottoms of the containers 21. Referring to the first of the webs 11, it will be noted that it passes over the top of the upper of the.couple of rollers a and-around approximately one half portion thereof, and then backwardly in reverse direction between the. two

rollers, and thence the said web travels rearwardly and passes in succession between the rollers of the successive couples of rollers b, c and d; The web of paper which is taken from the second of the rolls 6, as illustrated, travels through the solution of zinc chloride contained in the second of the containers 21, and thence over the top roller of the couple of rollers'b and around approximately half of the said roller and backwardly or in reverse direction between the rollers of the saidcouple. It is apparent that at this point the first and second webs 11 are united into a two-ply sheet or web. The same operation takes place with respect to the remaining two webs 11 shown in Fig. 1, the said webs being united successively by means of the two couples of rollers c and d with the previously united first and second webs 11, as illustrated in Fig. 1. In like manner the webs designated by the reference number 13, which are the last three webs shown in Fig. 1, are united. a

For the purpose of completing the gelatinization and causing the union of the webs which are brought into overlying relation with respect to each. other as described and as illustrated in Fig. 1 of the drawings, the rollers of the respective couples a, b, 0, etc. are heated. The heating thereof may be effected in any desired known manner but I prefer to effect the heating thereof by the introduction thereinto (the said rollers being tubular as shown) of a suitable heated fiuid, such as water or steam. The temperaturesto which the said sheets may be raised by the action of the heat of the rollers of the couples a, b, c,

etc., may range from about 38 C. to about 93 C.,

and the heat of the fluid supplied to the respective rollers of the couples may be governed accordingly. Except for their rotation the bottom rollers of the respective couples a, b, c, etc., are stationary, being journaled in stationary bearlugs mountedin openings provided in the opposits sides of the base 1. The top roller of each of the couples is movable verticallyrbeing sup-v ported in bearings 31 which are mounted in notches or slots 32 provided in the upper portions of the opposite sides of the base 1.. Springs 33 bear upon the said bearings 31 and hold or tend to hold them downwardly so as to cause the top roller of each ,of the couples to bear against thebottom roller of each of said couples or upon a sheet or web'of paper or fiber board which may be passing or traveling between the said rollers. The trunnions by which the rollers of the respec-- tive couples are supported upon the bearings 30- -and 31 are hollowand they are also extended as indicated in Fig. 4, and are provided with sprocket wheels indicated at 34 and 35. The extended journals of therolls of one couple, as indicated in Figs. 3 and 4, are provided with gears 36 and 37 which mesh with each other as shown. The

gear 36 is also in engagement with a. pinion 38 mounted upon one end of the shaft of a motor 39. Of course power for driving the pinion 38 may be supplied in any other way or from any other source. The driving of the pinion 38 causes rotation of the gear. 36, which in turn causes rotation of the gear 37. These gears being connected to the Journals of a couple of rollers as illustrated in Figs. 3 and 4, the said rollers are likewise rotated. For the purpose. of eilecting rotation of the rollers of all of the couples of the series the journals of the rollers of each couple are provided with sprocket wheels 34'and which are adapted to be engaged by sprocket chains 40 and 41.. It may be noted that the gears and the rollers are rotated in the direction indicated by the arrows 42' in Fig. 3. The rollers of the remaining couples are rotated in like or similar directions. For the purpose of supplying heated fluid,-

such as water or steam, to the hollow rolls of the respective couples of rolls, I have provided-a manifold pipe 43 which extends lengthwise'of and in adjoining relation to one side of the apparatus,

from which manifold branchpipes 44 extend,

which pipes are connected by means of laterally extending sections of pipe 45 and 46; These sections of pipe 45 and 46 are connected by means of couplings 47 to the outer ends of the journals of the rollers of the respective couples.- For the purpose of controlling'the. admissionof heated fluid to the hollow rollers of the respective couples- I have provided valves 48 in the sections of'pipe 45 and 46. These valves are shown in Fig. 4 of the drawings. The journals at the opposite ends of the rollers are also hollow and are connected by means of couplings 50 with the ends 'of sections of pipe 51 which in t u n are connected to branch pipes 53 having connection at their lower discharge ends to a manifold pipe 54 by which the fluid which has passed throughthe hollow rollers is or may be conveyed away. The branch pipes 51 are also provided with valves 55 which are adjustable to control thepassage of fluid through the said branch pipes. By properly regulating these valves the rate of fiow of th heating fiuid through the hollow rollers of he respective couples may be controlled and by such control the temperature of the said rollersmay be regulated the other hand,

The employment of sprocket chains 40 and 41 *to rotate the rollers of the respective couples causes rotation of all of the rollers at the same rate of speed. It will'be understood, however, that if desired, means may be provided whereby the bottom rollers may be caused to rotate at a slightly greater speed than the top rollers, or on it may be provided that the top rollers shall rotate at slightly greater speed than the bottom rollers. However, the rollers usually are and should be caused to rotate at the same speed, as is indicated in the drawings.

- done, a greater For the purpose of supporting and aiding in the rearward travel of the web between the adjoining couples of rollers in the series I have provided intermediate rollers 60 of relatively small diameter, the upper sides ,of which are located in a plane tangential to the upper sides of the bottom rollers of the respective couples. That relationship is clearly apparent from Fig. 1 of the drawings. Preferably the rollers'60 should be caused to rotate at a speed sufllcient to cause their peripheral surface to travel at the same speed as the speed of travel of the peripheral surfaces of the rollers of the respective couples a, b, c, etc.

In its passage between the rollers of the couple a the first of the webs 11 is not only subjected to heat but also to pressure, whereby its gelatinization is accelerated and its density and homogeneity of structure increased. As it passes between the rollers of the couple b it is joined by and united with the second of the webs 11 and both of the said webs are subjected to heat and pressure by the rollers of the couple b. In like manner t e third and fourth webs 11 are united with the pievious webs and 'with each other by the action of the rollers of the respective couples c and d. The location of these couples of rollers in succession as shown enables a successive kneading of and compressing action upon the webs of paper, so that a product having improved characteristics of density and homogeneity is produced. One reason why the product resulting from the operation is of improved character is that each of the webs is subjected to the full action of the heat and pressure of the top rollers of the successive couples of rollers. The arrangement and the operation are such also that there is no practical Jimit to the number of webs which may be; united. In other words, the apparatus provides means whereby sheets of vulcanized fiber of greater thickness of required quality may be made than heretofore has been practical. In like manner the couples of rollers e, f, and a operate to form athree-ply product 14 by effecting union of the three webs 13 of the last three rolls of the bottom series of rolls, It will be understood also that the operation is identically the same if the webs of papershould be taken from the topmost series of rolls 10.

While I have shown products of four-ply and three-ply, respectively, it will be apparent that a single product may be produced having a thickness equal to the combined thickness of a num- {her of sheets of vulcanized fiber, and'by extending the apparatus as is indicated at A may be uinber of rolls 6 and '7 may be supported from which paper may be taken, and consequently an added and indefinite number of sheets of vulcanized fiber may be produced simultaneously or else a single sheet having a thickness equal to the combined thickness of the plurality of sheets may be produced.

The four-ply sheet 12 is conducted from the 60, which is located between departing from adjoining roll may be ,..the, rollers of each pair the couples of rollers d and e. downwardly between the pair of rollers wand over the rollers '11 by which it is supported, and thence between the pairs of rollers 72, from the last of which it is conducted through one or more tanks, one being shown at '15, containing zinc chloride in more dilute solution in water than that held in the containers 21. Likewise the sheet or web 14 previously referred to is conducted betweenpairs 74' of rollers from the last of which it is conducted to the same tanks as those through which the sheet 12 is conducted. The sheets 12 and 14, respectively, are guided through the tank 75 by means of pairs of rollers '16 and 7'7 and are guided therefrom by means of pairs of rollers '18 and '19. To aid in causing the vulcanized fiber webs to travel rearwardly through and from the machine I have provided drawing rollers, indicated as a whole at 80, the said rollers being driven by means or a motor a portion of which is indicated at 81. I

After having passed through and beyond the solution contained in the tank 75, or additional tanks if any be employed, the sheets are subjected to the usual puring process.

Thepurpose of passing the sheets through one or more tanks of a relatively dilute solution of zinc chloride in water is to remove therefrom the strong zinc chloride from the surface of the sheets which was deposited thereon in the passage of the sheets through the relatively strong solution held in the containers 21. By thus partially removing the strong zinc chloride from the surfaces of the sheets they will not take up stain or become discolored from the subsequent puring" operation, nor will the sheets stick together 11 cut into individual sheets and laid one upon the other to make up a truck-load, as actually may happen in practice.

fIhe foregoing constitutes the essential and distinctive thought of my improved process and the apparatus by means of which I prefer to carry out its steps, but it will be, of course, understood that the same may be combined with various other steps or details without aifecting the peculiar results obtained. Furthermore, that changes and modifications may be resorted to without the spirit of my invention.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. An apparatus for producing a multi-ply web of vulcanized fiber, comprising means for-supporting in adjoining relation to each other a series of rolls of cated laterally of the respective rolls of paper, which container is adapted to'hold gelatinizing agents of the same qr different concentrations and temperatures ,and each container having means whereby a web of paper taken from the guided through the gelatinizing agents contained therein, pairs of rollers located in advance of the respective containers, being located one above the other and the top roller adapted to rest upon the bottom roller and the web of paper which passes through the adjoining container... being conducted over the topmost roller and between the two rollers whereby heat and pressure are applied thereto, the web of paper from the first of the rolls of paper passing betweenthe rollers of all of a selected number of pairs of rollers and the webs of paper from'succeeding rolls passing between the rollers of a number of couples one less than the number between which the next preceding web of paper passes, and means for to the said sheets by for conveying the sheets produced by the combin-- losic material to lure action of conveying the sheet produced by the union of the said webs from the said apparatus,

2. An apparatus for producing a multi-ply Web of vulcanized fiber, comprising means for supporting a plurality of rolls of webs 01' paper in adjoining relation to each other, a container located laterally'of and below each roll which containers are adapted to contain gelatinizing agents of the same or different concentrations and temperatures, means located within each o1 said containers for contacting with and guiding the webs of paper from the said rolls through the gelatinizing agents contained in the said containers, a couple of rollers located in advance 01' each container, which rollers are located'one above the other and the top roller exerting pressure upon each couple and being extended rearwardly between the said rollers, the said webs of paper being brought successively into contact with each other at uniform distances along the composite sheet, and union thereof successively effected by heat and pressure applied thereto by the rollers of the said couples.

3. An apparatus for producing a multi-ply web of vulcanized fiber, comprising means for supporting a. plurality of rolls of webs of paper in series, containers located laterally of and below the respective rolls of paper which containers are adapted to hold gelatinizing agents of the same or different concentrations and temperatures, and each container having means therein for contacting with and guiding a web of paper therethrough from the adjoining associated roll of paper, couples of rollers located in advance 01' and in cooperative relation to the respective con-' tainers, the upper roller of each couple resting vupon the lower roller 01' the couple, means for heating the said rollers and the webs of paper after leaving the respective containers, the said webs passing over and partially around the top roller of each of the couples of rollers and the said webs passing between the said rollers and thence toward the rear of the apparatus, the webs from successive rolls of paper being successively united with paper from the preceding rolls of paper at predetermined distances along the composite sheet thus formed, such union being eflected by the application of heat and pressure the said rollers, and means ing 01 the said webs of paper away from the sheet-forming portion 01' the said apparatus.

4. A method or making a multi-ply web of indurated fiber which comprises the steps of subjecting a web of cellulosic material to the action of a gelatinizing bath of desired concentration and temperature, subjecting said web'to the action or heat and pressure to carry its gelatinization sufilciently far to render said web suitable for incorporation into a multi-ply web of indurated fiber, subjecting a second web of cellua gelatinizing bath of desired concentration and temperature which are not necessarily the same as those of the first bath, superposing the second treated web upon the first and subjecting the the action 01 heat and pressure to carry the gelatinization oi the second web sufficiently for to render said web suitable for incorporation into a multi-ply web of indurated-fiber.and to si-.

bath of indurated fiber which comprises the steps oi sub- Jecting a web 01' cellulosic material to the action 01' a gelatinizing bath of desired concentration tion sufilciently far to render said web suitable for incorporation into a multi-ply web 01' indurated fiber, subjecting a second web 01' cellulosic material to the action of a gelatinizing bath of desired concentration and temperature which are not necessarily the same as those of the first bath. superposing the second treated web upon the first, subjecting the superposed webs to the action of heat and pressure to carry the gelatinization oi. the second web sufilciently far to render said web suitable for incorporation into a multi-ply web 01' indurated fiber and to simultaneously unite said webs into a single dense homogeneous web of indurated fiber and continuing the process with as many additional webs oi cellulosic material as necesary to build up a web 01 indurated fiber oi desired thickness.

6. An apparatus for producing a multi-ply web vulcanized fiber comprising the combination means to subject a webot cellulosic material to the action of a gelatinizing bath, means to subject said web to the action of heat and pressure to carry its gelatinization sufilciently far to render said web suitable for incorporation into a multi-ply web of indurated fiber,

sufilciently far to render said into a. multi-ply indissolubly unite 7. An apparatus for producing a multi-ply web of vulcanized fiber comprising the combination of means to subject each of a plurality of webs of cellulosic material to a separate gelatinizing predetermined concentration and tem perature, means to subject one of said webs to the action oi heat and pressure to carryits gelatinization sufilciently tar to render said web suitable for incorporation into a multi-ply web 01' indurated fiber, means to superpose a second web upon the first, means to posed webs to the action 01' heat and pressure to carry the gelatinization oi the second web sumciently far to render said web suitable for incorporation into a multi-ply web 01. indurated fiber and to simultaneously cause it to unite with the first web and means for superposing and uniting as many of the remaining webs of gelatlnized ot'a gelatinizing bath, means to subject each ofeach 01'. said selected group of treated webs.

9. an apparatus for producing a predetermined plurality of webs oi a roup of webs into one dense, homogeneous multinumber of webs of indurated fiber, each having a predetermined number of plies, comprising means for subjecting each of a plurality of webs of cellulosic material to the action of a gelatinizing agent, means to subject each of a group of webs selected from said treated webs to the action of heat and pressure to carry their gelatinization sufliciently far to render said web suitable for incorporation'into a multi-ply web of indurated fiber, means to superpose one of the remaining webs upon each of said heat and pressure treated webs and means to apply heat and pressure to each set of superposed webs to form as many webs of dense, homogeneous indurated fiber as there are webs in the group first selected.

10. A method of producing multi-ply webs of indurated fiber comprising the steps of subjecting each of a plurality of webs of paper to the action of a gelatinizing agent, subjecting each of a group of webs selected from said treated webs to the action of heat and pressure to carry their gelatinization sufficiently far to render said web suitable for incorporation into a multi-ply web of indurated fiber and building up a laminated web of indurated fiber of desired thickness upon each of said selected groups of treated webs.

11. A method of producing multi-ply webs of indurated fiber comprising the steps of subjecting each of a plurality of webs of paper to the action of a gelatinizing agent, subjecting each of a group of webs selected from said treated webs to the action of heat and pressure to carry their dense, homogeneous indurated fiber as there are webs in the selected group.

12. A continuous method of producing a laminated product of vulcanized fiber which consists laminating a plurality of continuously moving webs of gelatinized paper while said webs are maintained in substantially flat condition.

13. A method of producing a laminated product of vulcanized fiber which consists in continuously forming a substantially fiat web of indurated fiber and then progressively and continuously superposing one or more layers of gelat-' inized paper upon said fiat web and consolidat-w ing the assembly by the means of heat and pressure while both said web and superposed layers are maintained in substantially flat condition.

14; An apparatus for producing a web of vulcanized fiber having a predetermined number of plies said apparatus comprising a series of units equal in number to the number of plies in the finishedproduct and arranged in parallel relation along the length of the web to be produced thereby, each unit consisting of a supply roll, a gelatinizing bath disposed below and to onev side of said supply roll and two closely spaced heat and pressure applying cylinders disposed below the said supply roll, whereby a web of paper may be drawn from the supply roll of the first unit, conducted through the corresponding gelatinizing bath, around the upper of the corresponding cylinders and between the corresponding cylinders to be formed into the base web upon which the webs of paper treated in each of the other units may be superposed and consolidated therewith by means of the heat and pressure appressure applying cylinders disposed below and in close relation to each of said supply rolls, and a gelatinizing bath disposed to one side of each of said set of cylinders, whereby a web of paper 

